SAN DIEGO – There is, after so many years of the position being light in top-end talent, an actual No. 1 receiver on the Chargers.

A receiver. Not a ridiculously fluid tight end. Not a running back who catches passes as well as any ever has. A receiver.

His name is Vincent Jackson, and he is the poster child for patience.

“It's hard to say he's the most improved player, because he came in with a lot of talent,” quarterback Philip Rivers said. “But he's improved tremendously. He's developed himself into a go-to guy.”

That's saying a lot, Rivers knows, because he has a fair amount of guys to go to. There is tight end Antonio Gates, who actually had one more reception than Jackson in 2008 but almost 400 fewer yards. There is running back LaDainian Tomlinson, who in 2003 set the team record with 100 receptions and has never had fewer than 50 catches in a season. There is receiver Chris Chambers, who Rivers relied on heavily in 2007.

But the steady improvement in Jackson over the past 2½ years has resulted in his being as dangerous a weapon as Rivers possesses.

His rookie season, in '05, Jackson caught three balls. He wasn't in games often and was targeted just eight times by then-quarterback Drew Brees.

Midway through the next season, Jackson became more a part of the offense as he matured in his understanding of the game and Rivers spread the ball around. Jackson caught 19 of his 27 passes and four of his six touchdowns that year in the final seven games.

In '07, he had his first career 100-yard game in the playoffs against Tennessee and 93 yards in each of the next two playoff games.

“We had to use more weapons with injuries and things that happened (in '07),” Jackson said. “From there, it just flowed over to last season, and Philip gained more confidence in what he was doing and had a better feel for me.”

Time and again in '08 Jackson made circus catches deep downfield as he amassed 1,098 yards and seven touchdowns on 59 receptions. He was the Chargers'first 1,000-yard receiver since Curtis Conway in 2001. Jackson's 18.6-yard average was fourth in the NFL and tops among those with more than 50 receptions.

To Rivers, it sometimes appears Jackson can catch anything he throws. At 6 feet 4 and 230 pounds, Jackson is tall and physical and also blessed with an ability to hang in the air and seemingly weave his body and hands through defenders.

But it wasn't until Jackson assimilated the difficulties of precise route running, reading defenses and understanding what his quarterback sees that he became what he is now.

“This game is 75 percent mental,” Jackson said. “It's about understanding what's expected of you and the concept of our offense better and having a relationship with the quarterback.”

Said Rivers: “His understanding of the game has helped he and I the most.”

Chargers coach Norv Turner has often praised Jackson for being the same worker he is in practices that he is in games. Jackson does not take plays off, and he is among the best blocking receivers in the game.

“I continued to do repetitions in practice my first two years and by the time my third year came around, it was like 'Bam.' Everything was boom, boom. No thought,” Jackson said. “You think a lot as a rookie and a second-year player. Your natural ability sometimes gets hindered. Now that I don't have to think so much about what I'm doing, I'm out there letting my raw skills show. It's fun.”

Whatever Jackson does on the field this year, his lingering legal issues and his expiring contract will also be ever-present.

Jackson was arrested on suspicion of drunken driving the week before the Chargers' playoff game at Pittsburgh in January. That case is on appeal and likely will not be resolved until 2010, almost definitely precluding the Chargers from losing Jackson to a suspension this season.

But, in that Jackson was already convicted of DUI in 2006, a possible suspension in 2010 looms. And with his contract up after this season, the Chargers are evaluating both his play and his off-field behavior.

“I'm the same football player,” Jackson said. “It doesn't change the character person I am. Obviously, it's something that's unfortunate. But I definitely have a positive outlook about it. My teammates have confidence in me, so I don't worry that much about it.”

It's the outlook of a No. 1 receiver.

“(The 2008 season) just really gave me a platform because I set the bar for myself, and I know I can do better,” Jackson said. “We want to be as dynamic an offense as we can be. And I have individual goals, sure. I want to do as well as I did – even better – this year.”